Copyright: 1996 - 2024
BSEE - KB3UON
RF Cafe began life in 1996 as "RF Tools" in an AOL screen name web space totaling
2 MB. Its primary purpose was to provide me with ready access to commonly needed
formulas and reference material while performing my work as an RF system and circuit
design engineer. The World Wide Web (Internet) was largely an unknown entity at
the time and bandwidth was a scarce commodity. Dial-up modems blazed along at 14.4 kbps
while tying up your telephone line, and a nice lady's voice announced "You've Got
Mail" when a new message arrived...
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My Hobby Website:
cavity filter - RF Cafe Forums
RF Cafe Forums closed its virtual doors in 2012 mainly due to other social media
platforms dominating public commenting venues. RF Cafe Forums began sometime around
August of 2003 and was quite well-attended for many years. By 2010, Facebook and
Twitter were overwhelmingly dominating online personal interaction, and RF Cafe
Forums activity dropped off precipitously. If the folks at
phpBB would release a version with integrated
sign-in from the major social media platforms, I would resurrect the RF Cafe Forums,
but until then it is probably not worth the effort. Regardless, there are still
lots of great posts in the archive that ware worth looking at.
Below are the old forum threads, including responses to the original posts.
|-- Amateur Radio
Gripes & Humor
-- CAE, CAD, &
Test & Measurement
Post subject: cavity filter
Unread postPosted: Wed Feb
11, 2004 1:40 am
I am a RF engineer and I'd like to
implement narrow cavity filters for catv.
bandpass examples are 62.25MHz,
399.25MHz and 793.25MHz which must reject 25dB 7MHz apart of these pilot
notch examples are same frequencies but also 7MHz wide
to suppress a TV channel.
I am using Eagleware softwares.
understand the mechanical part of implementing a cavity filter (dimensions,
how to hold the vertical coils, how to fix the tuning screws,...)
I have found the Zverev old book but it is no as clear for a beginner
in this field.
Can somebody help me ?
Post subject: cavity filter
Fri Feb 13, 2004 2:47 pm
Welcome to Forum!
filters like any other filters (passive or active) require experience,
but you are moving in the right direction here. There are some many
technical issues to discuss in order to accomplish this design. Before,
I help you design (if you want me to help) these cavities, you must
provide some critical information such as: Max RF output power, Max
Insertion Loss (desirable), Is there Max Time Delay and Phase Linear
requirement (remember you are dealing with video and audio)? ...These
are high Q coaxial cavities. Size, loop setting, critical coaxial cable
length...etc are very critical to know in order to design these cavities.
For 62.25MHz, it is not going to be that small and customized rack mounting
panel will be required! As for 399.25MHz and 793.25MHz, you will be
able to fit them into standard 19” rack mounting panel. Again, you will
have to decide on rack mounting panel. For your information, if you
choose round or square cavity, it will not make any difference as far
the performance goes! In order to give you an exact answer on electrical &
mechanical specs, I suggest you contact me via email at firstname.lastname@example.org
or email@example.com and I will be keen to help you.
Post subject: cavity
Unread postPosted: Fri Feb 13, 2004 8:37 pm
I understand you want to design these cavity filters. As an alternative
and in case you would like to buy them there are many CATV (cable tv)
filters manufacturing around the world. Following are some companies: